1. Field of the Invention
This invention relates to the field of radio receiving and transmitting equipment and especially to the frequency controlling portions of such equipment. In the context of its entirety, the invention is particularly well suited for incorporation into a radio transceiver, such as those employed for receiving aircraft navigation signals and for receiving and transmitting communication signals to and from aircraft; in a more specific context, however, the invention provides a number of improvements also having individual utility in various types of radio equipment generally.
2. Description of the Prior Art
The art of radio receivers, transmitters and transceivers is now a relatively mature one in which most known recent improvements have tended either to narrowly focus upon some isolated specific part of such equipment or to seemingly fall within the category of natural evolutionary conversion of portions of such equipment to employ newly available components for performing the usual functions in what is still essentially the same old way.
It is true, of course, both that (with the exception of the structures utilized to accomplish optimized inter-stage coupling over an increased bandwidth) this invention intentionally employs modern but commonly available individual components for purposes of economy and employs to a considerable degree classes of individual circuits whose genus is well known (e.g., digital frequency synthesizers, voltage controlled oscillators, tuned active filters, etc.).
However, insofar as is known, neither the involved individual improvements nor the advantageous combination and sub-combinations of same provided by this invention have heretofore been employed or proposed by others. Moreover, it is believed that prior devices have neither achieved the desirable results provided by this invention nor taught that such results should be sought in a similar fashion.